AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

[turbofan] Simplify reduction if IfTrue and IfFalse and fix bugs.

Browse Source 
R=mstarzinger@chromium.org
BUG=chromium:451958
LOG=Y

Review URL: https://codereview.chromium.org/880533002

Cr-Commit-Position: refs/heads/master@{#26276}
This commit is contained in:
titzer 2015-01-26 08:11:17 -08:00 committed by Commit bot
parent ecfbe909f3
commit 7c81161b97
4 changed files with 97 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
src/compiler/control-reducer.cc
View File

@ -357,8 +357,10 @@ class ControlReducerImpl {
// Reduce branches, phis, and merges.
switch (node->opcode()) {
case IrOpcode::kBranch:
return ReduceBranch(node);
case IrOpcode::kIfTrue:
return ReduceIfTrue(node);
case IrOpcode::kIfFalse:
return ReduceIfFalse(node);
case IrOpcode::kLoop:
case IrOpcode::kMerge:
return ReduceMerge(node);
@ -480,30 +482,31 @@ class ControlReducerImpl {
}
// Reduce branches if they have constant inputs.
Node* ReduceBranch(Node* node) {
Decision result = DecideCondition(node->InputAt(0));
if (result == kUnknown) return node;
TRACE(("BranchReduce: #%d:%s = %s\n", node->id(), node->op()->mnemonic(),
(result == kTrue) ? "true" : "false"));
// Replace IfTrue and IfFalse projections from this branch.
Node* control = NodeProperties::GetControlInput(node);
for (Edge edge : node->use_edges()) {
Node* use = edge.from();
if (use->opcode() == IrOpcode::kIfTrue) {
TRACE((" IfTrue: #%d:%s\n", use->id(), use->op()->mnemonic()));
edge.UpdateTo(NULL);
ReplaceNode(use, (result == kTrue) ? control : dead());
control = NodeProperties::GetControlInput(node); // Could change!
} else if (use->opcode() == IrOpcode::kIfFalse) {
TRACE((" IfFalse: #%d:%s\n", use->id(), use->op()->mnemonic()));
edge.UpdateTo(NULL);
ReplaceNode(use, (result == kTrue) ? dead() : control);
control = NodeProperties::GetControlInput(node); // Could change!
}
Node* ReduceIfTrue(Node* node) {
Node* branch = node->InputAt(0);
DCHECK_EQ(IrOpcode::kBranch, branch->opcode());
Decision result = DecideCondition(branch->InputAt(0));
if (result == kTrue) {
// fold a true branch by replacing IfTrue with the branch control.
TRACE(("BranchReduce: #%d:%s => #%d:%s\n", branch->id(),
branch->op()->mnemonic(), node->id(), node->op()->mnemonic()));
return branch->InputAt(1);
}
return control;
return result == kUnknown ? node : dead();
}
// Reduce branches if they have constant inputs.
Node* ReduceIfFalse(Node* node) {
Node* branch = node->InputAt(0);
DCHECK_EQ(IrOpcode::kBranch, branch->opcode());
Decision result = DecideCondition(branch->InputAt(0));
if (result == kFalse) {
// fold a false branch by replacing IfFalse with the branch control.
TRACE(("BranchReduce: #%d:%s => #%d:%s\n", branch->id(),
branch->op()->mnemonic(), node->id(), node->op()->mnemonic()));
return branch->InputAt(1);
}
return result == kUnknown ? node : dead();
}
// Remove inputs to {node} corresponding to the dead inputs to {merge}
@ -578,12 +581,19 @@ Node* ControlReducer::ReduceMergeForTesting(JSGraph* jsgraph,
}
Node* ControlReducer::ReduceBranchForTesting(JSGraph* jsgraph,
Node* ControlReducer::ReduceIfNodeForTesting(JSGraph* jsgraph,
CommonOperatorBuilder* common,
Node* node) {
Zone zone;
ControlReducerImpl impl(&zone, jsgraph, common);
return impl.ReduceBranch(node);
switch (node->opcode()) {
case IrOpcode::kIfTrue:
return impl.ReduceIfTrue(node);
case IrOpcode::kIfFalse:
return impl.ReduceIfFalse(node);
default:
return node;
}
}
}
}

2
src/compiler/control-reducer.h
View File

@ -25,7 +25,7 @@ class ControlReducer {
// Testing interface.
static Node* ReducePhiForTesting(JSGraph* graph,
CommonOperatorBuilder* builder, Node* node);
static Node* ReduceBranchForTesting(JSGraph* graph,
static Node* ReduceIfNodeForTesting(JSGraph* graph,
CommonOperatorBuilder* builder,
Node* node);
static Node* ReduceMergeForTesting(JSGraph* graph,

51
test/cctest/compiler/test-control-reducer.cc
View File

@ -17,6 +17,8 @@ using namespace v8::internal::compiler;
static const size_t kNumLeafs = 4;
enum Decision { kFalse, kUnknown, kTrue };
// TODO(titzer): convert this whole file into unit tests.
static int CheckInputs(Node* node, Node* i0 = NULL, Node* i1 = NULL,
@ -175,10 +177,25 @@ class ControlReducerTester : HandleAndZoneScope {
CheckInputs(end, expect);
}
void ReduceBranch(Node* expect, Node* branch) {
Node* result =
ControlReducer::ReduceBranchForTesting(&jsgraph, &common, branch);
CHECK_EQ(expect, result);
void ReduceBranch(Decision expected, Node* branch) {
Node* control = branch->InputAt(1);
for (Node* use : branch->uses()) {
if (use->opcode() == IrOpcode::kIfTrue) {
Node* result =
ControlReducer::ReduceIfNodeForTesting(&jsgraph, &common, use);
if (expected == kTrue) CHECK_EQ(control, result);
if (expected == kFalse) CHECK_EQ(IrOpcode::kDead, result->opcode());
if (expected == kUnknown) CHECK_EQ(use, result);
} else if (use->opcode() == IrOpcode::kIfFalse) {
Node* result =
ControlReducer::ReduceIfNodeForTesting(&jsgraph, &common, use);
if (expected == kFalse) CHECK_EQ(control, result);
if (expected == kTrue) CHECK_EQ(IrOpcode::kDead, result->opcode());
if (expected == kUnknown) CHECK_EQ(use, result);
} else {
UNREACHABLE();
}
}
}
Node* Return(Node* val, Node* effect, Node* control) {
@ -1028,7 +1045,7 @@ struct While {
TEST(CBranchReduce_none1) {
ControlReducerTester R;
Diamond d(R, R.p0);
R.ReduceBranch(d.branch, d.branch);
R.ReduceBranch(kUnknown, d.branch);
}
@ -1037,7 +1054,7 @@ TEST(CBranchReduce_none2) {
Diamond d1(R, R.p0);
Diamond d2(R, R.p0);
d2.chain(d1);
R.ReduceBranch(d2.branch, d2.branch);
R.ReduceBranch(kUnknown, d2.branch);
}
@ -1050,13 +1067,7 @@ TEST(CBranchReduce_true) {
for (size_t i = 0; i < arraysize(true_values); i++) {
Diamond d(R, true_values[i]);
Node* true_use = R.graph.NewNode(R.common.Merge(1), d.if_true);
Node* false_use = R.graph.NewNode(R.common.Merge(1), d.if_false);
R.ReduceBranch(R.start, d.branch);
CHECK_EQ(R.start, true_use->InputAt(0));
CHECK_EQ(IrOpcode::kDead, false_use->InputAt(0)->opcode());
CHECK(d.if_true->IsDead()); // replaced
CHECK(d.if_false->IsDead()); // replaced
R.ReduceBranch(kTrue, d.branch);
}
}
@ -1068,13 +1079,7 @@ TEST(CBranchReduce_false) {
for (size_t i = 0; i < arraysize(false_values); i++) {
Diamond d(R, false_values[i]);
Node* true_use = R.graph.NewNode(R.common.Merge(1), d.if_true);
Node* false_use = R.graph.NewNode(R.common.Merge(1), d.if_false);
R.ReduceBranch(R.start, d.branch);
CHECK_EQ(R.start, false_use->InputAt(0));
CHECK_EQ(IrOpcode::kDead, true_use->InputAt(0)->opcode());
CHECK(d.if_true->IsDead()); // replaced
CHECK(d.if_false->IsDead()); // replaced
R.ReduceBranch(kFalse, d.branch);
}
}
@ -1356,10 +1361,10 @@ TEST(CNonTermLoop_big2) {
Branch b1(R, R.p0);
Node* rt = R.graph.NewNode(R.common.Return(), R.one, R.start, b1.if_true);
Branch b2(R, R.zero, b1.if_false);
Node* loop = R.graph.NewNode(R.common.Loop(2), b1.if_false, R.start);
Branch b2(R, R.zero, loop);
loop->ReplaceInput(1, b2.if_false);
Node* rf = R.graph.NewNode(R.common.Return(), R.zero, R.start, b2.if_true);
Node* loop = R.SetSelfReferences(
R.graph.NewNode(R.common.Loop(2), b2.if_false, R.self));
Node* merge = R.graph.NewNode(R.common.Merge(2), rt, rf);
R.end->ReplaceInput(0, merge);

31
test/mjsunit/regress/regress-451958.js Normal file
View File

@ -0,0 +1,31 @@
// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax
function k() { throw "e"; }
var a = true;
var a = false;
function foo(a) {
var i, j;
if (a) {
for (i = 0; i < 1; j++) ;
for (i = 0; i < 1; k()) ;
for (i = 0; i < 1; i++) ;
}
}
%OptimizeFunctionOnNextCall(foo);
foo();
function bar() {
var __v_45;
for (__v_45 = 0; __v_45 < 64; __v_63++) {
}
for (__v_45 = 0; __v_45 < 128; __v_36++) {
}
for (__v_45 = 128; __v_45 < 256; __v_45++) {
}
}
%OptimizeFunctionOnNextCall(bar);
assertThrows(bar);